mcp-shield

Sorry, but this will never work very well. The tool contains a bunch of "denylist regexes", i.e. `user (should not|must not|cannot) see` But these can easily be bypassed. Any real security tool should use allowlists, but that is ofc much harder with natural languages. MCP-Shield can also analyse using Claude, but that code contains an easy to exploit prompt injection: https://github.com/riseandignite/mcp-shield/blob/19de96efe5e...

That was faster than expected - here's the merged commit implementing the --identify-as flag: https://github.com/riseandignite/mcp-shield/commit/e7e2a6c04.... Thanks again!

I noticed the growing security concerns around MCP (https://news.ycombinator.com/item?id=43600192) and built an open source tool that can detect several patterns of tool poisoning attacks, exfiltration channels and cross-origin manipulations. MCP-Shield scans your installed servers (Cursor, Claude Desktop, etc.) and shows what each tool is trying to do at the instruction level, beyond just the API surface. It catches hidden instructions that try to read sensitive files, shadow other tools' behavior, or exfiltrate data. Example of what it detects: - Hidden instructions attempting to access ~/.ssh/id_rsa - Cross-origin manipulations between server that can redirect WhatsApp messages - Tool shadowing that overrides behavior of other MCP tools - Potential exfiltration channels through optional parameters I've included clear examples of detect